The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Proton-exchange membrane (PEM) fuel cells are well known. In a PEM fuel cell, hydrogen atoms are ionized in an anode, migrate through a specialized membrane as hydrogen cations (protons), and combine with oxygen anions at a cathode to form water. Electrons from the hydrogen flow from the anode through an external circuit to the cathode, thereby creating usable electricity.
Fuel cell assemblies comprise a plurality of individual fuel cells stacked together and connected in electrical series. Each individual fuel cell typically includes a membrane electrode assembly (MEA) including a special membrane and having a gas diffusion layer on each side thereof. The MEA is sandwiched between bipolar plates that include gas flow channels formed in the surface thereof. Each individual fuel cell requires a seal or gasket along all outer edges and around all openings to prevent leaking of reactant gases and coolant. It is known to use separate die-cut or molded rubber gaskets, installed between the plates during assembly of a fuel cell stack. However, a serious problem exists in locating the gaskets properly with respect to the openings to be sealed. A misaligned gasket can cause leaks, stack failure, and even broken bipolar plates. Further, using separate gaskets adds significantly to the overall time of stack assembly.
The present disclosure provides an MEA with a seal that is integrally molded to the gas diffusion layers and are provided with interlocking features. A pair of gas diffusion layers with integrally molded seals are mated together with the interlocking features and a catalyst coated membrane therebetween to complete an MEA assembly.
Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.